You, Who by Your unspeakable goodness has created us, tell us, why did You fill our lives with grief? Does not Your mercy make You to pity our sufferings? Why do You grant me being and later take it away through a painful death? I do not enjoy, says God, your illnesses, o man. But, out of the seeds of your grief and sorrow, I want to bring forth for you fruits of eternal and majestic joy. I imprinted the law of death and destruction not only in your body, but also in every object of this visible world. I commanded the whole world, together with your body, to cry out to you that this life is not the true and real life, and there is nothing permanent here to which your heart should become attached through justifiable love. When you do not hearken unto the threatening voice of the entire universe, then My paternal mercy, which always wishes you unlimited good, compels Me to lift the sceptre of chastisement. When I torment you with temptations, wear you out with illness, with pangs of remorse, it is that you might abandon your folly, become wise, cease seeking after shadows and return to the path of salvation. My unutterable mercy and unlimited love for human beings compelled Me to take your flesh upon Myself; through My abasement I have revealed the greatness of God to the human race (cf. John 14:9). By suffering on the Cross for the salvation of men, whom I desire to draw to Myself, I first afflict them with grief, and with these arrows of affliction I deaden their hearts to temporary pleasures. The sceptre of punishment is an emblem of My love for men. [...] Glory by for all things to the most merciful God, Who pours out His ineffable blessings upon us in every circumstance. For the Fount of Goodness can produce no other waves but the waves of goodness. Man, often not recognising this, murmurs against the All-Gracious One.
Saint Macarius of Optina